UNISEC Europe CSID An Advanced Efficient Electrical Interface Standard for CubeSats

Transcription

1 UNISEC Europe CSID An Advanced Efficient Electrical Interface Standard for CubeSats 4 th IAA Conference on University Satellite Missions and CubeSat Workshop Oliver Ruf 1

2 Motivation for a Standardization of Electrical Interfaces of CubeSats: Experience? UWE-1 UWE-2 UWE-3 Oliver Ruf 2

3 Motivation for a Standardization of Electrical Interfaces of CubeSats: Global market 474 scheduled and performed launches of NanoSatellites in satellites operational end of 2016 Key aspects Performance: miniaturization is key driver to limit costs Fast Development Cycle: design, iterate, and launch within a few months Modern Production: production, integration & test: from high-tech manufactures to batch production Oliver Ruf 3

4 Motivation for a Standardization of Electrical Interfaces of CubeSats: Global subsystem market Oliver Ruf 4

5 Motivation for a Standardization of Electrical Interfaces of CubeSats: Durability & Reliability of all launched CubeSats failed to meet their mission goal different studies show this is mostly due to insufficient functional testing at system-level Oliver Ruf 5

6 Motivation for a Standardization of Electrical Interfaces of CubeSats standardization is the key to economical utilization of small satellites in large numbers enables fast and reliable development, integration and verification standardized interfaces facilitate access to the system and increase testability and robustness Oliver Ruf 6

7 Chances for a Standardization of Electrical Interfaces of CubeSats allow fast and compact integration simple maintenance of integrated bus support steep learning curve Increase of standardized monitoring and protection of subsystems support for scalability simplifies re-utilization and extension of subsystem designs standardized support for testing and debugging (in-orbit) re-programming of (integrated) subsystems Oliver Ruf 7

8 Limitations of current approaches PC/104: 104 signals, many undefined and inconsistently used by different manufacturers, very large connector (20% of (inter-)board space) all signals pass all connectors between source and sink increased power loss and noise many important signals are currently not present on main connector harnessing required for: solar panel inputs flight/kill switch logic test, debug, programming interface for individual subsystems Oliver Ruf 8

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10 Limitations of current approaches often missing signals e.g. sync signal for time/clock synchronization between subsystems Lack support for redundancy concepts separate unregulated battery power paths redundant data communication buses, concept for redundancy selection dedicated communication buses for crucial subsystem control (e.g. OBC-COMM, OBC-EPS) Oliver Ruf 10

11 UNISEC Europe Bus Generalized Debug & Maintenance Interface modular architecture based on backplane debug support for ANY microcontrollers on ALL subsystems (via OBC) full access to each subsystem via umbilical even when satellite is completely / tightly integrated external debug interface (extra standardized interface for stand-alone operation) provided by USB-Interface Oliver Ruf 11

12 UNISEC Europe Bus Digital Communication dedicated signal lines for control of most crucial standard subsystems, e.g.: OBC-COMM: dedicated serial communication lines for redundant communication subsystem OBC-EPS: dedicated control lines for redundant power paths redundant data communication buses, e.g.: 2x I2C: standard low rate / low power consumption communication for subsystem control and housekeeping and 2x M-LVDS (full duplex: 8 pins) for high rate / high power consumption communication for payload data bus, high speed downlink from data pool time synchronization between subsystems (pulse per second) Oliver Ruf 12

13 UNISEC Europe Bus Modular Distributed Electrical Power System Distributed Power Generation MPPT circuitry can be part of more intelligent solar panels can directly supply (redundant) unregulated power bus Minimal impact on required signals on satellite bus Power System capabilities scale with connected power generators Optimal design of MPPT circuitry w.r.t. solar panel Supports arbitrary number of panels with heterogeneous performance Oliver Ruf 13

14 UNISEC Europe Bus Modular Distributed Electrical Power System Distributed Power Distribution standardized subsystem interface control circuitry included on ALL subsystems power switch, monitoring, protection (OV, UV, OC) optimized for actual subsystem minimizes impact on required signals on satellite bus (no dedicated switched power line for each potential subsystem) selective isolation of data interface from satellite bus required for proper partial power down, avoids current leakage for switched off subsystems can also handle data bus or power bus redundancy selection in a standardized way undesired current leakage via data interface of powered down CMOS device UNISEC Europe Standard Interface Control Circuit Oliver Ruf 14

15 UNISEC Europe Bus CubeSat Subsystem Interface Definition External Debug Interface easy stand-alone operation of subsystem debug communication (UART via USB bridge) microcontroller programming and insystem-debugging (JTAG, SBW, SWD) supply by USB power (5V, 3.3V, unregulated bus) Power Control Circuit controlled by OBC via redundant I²C bus power switch power monitoring (voltage, current) power protection optimized for specific subsystem (over-voltage, under-voltage, overcurrent, i.e. latchup) Satellite Bus Connector compact and robust backplane redundant power, high-speed and low-speed digital buses dedicated signals for reset, time sync, deployment logic internal debug interface (communication, programming, and debugging after integration and in-orbit) Interface Control Circuit selective bus isolation prevents current leakage for partial power down allows bus routing, redundancy selection controlled by OBC Oliver Ruf 15

16 UNISEC Europe Bus Satellite Development Board supports flexible and efficient satellite development allows rapid system assembly for efficient functional integration testing provides comfortable access to all relevant interfaces on the bus for efficient measuring and testing integrates UNISEC umbilical line specification providing a USB interface and various programmer interfaces simulates OBC or subsystems by integrated powerful MCU Oliver Ruf 16

17 UNISEC Europe Bus Implementations & Missions Oliver Ruf 17

18 Conclusions Small Connector enables very tight integration decreases launch cost drastically Increases flexibility, efficiency and robustness Prevents you from errors and enables rapid & reliable development, integration and testing, interchangeability, Open Source download specifications: Oliver Ruf 18

19 PS: Back to UWE-3 Integration and final testing took only 2 hours Fully operational since 21 st Nov today 1489 days HAPPY BELATED BIRTHDAY UWE-3 Oliver Ruf 19

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